A motor-driven vehicle, such as an electric vehicle or a hybrid car, has a small running sound compared with combustion engine vehicles, and it is therefore difficult for surrounding pedestrians to perceive the running of such a motor-driven vehicle. Therefore, for the purpose of alerting an area surrounding a motor-driven vehicle running to the danger due to an approach of the vehicle, efforts to emit a warning sound, such as pseudo noise, directed outside a motor-driven vehicle running have been spread.
On the other hand, while a warning sound is emitted in a normal state, equipment of a sound emission temporary stop switch is also permitted provided that it is used only in a case in which the safeness of the surrounding area is ensured. When the vehicle is running through an area in which no pedestrians are walking, the driver can stop the emission of the warning sound (pseudo noise) by using the sound emission temporary stop switch.
However, when the driver can control the emission and stop of the warning sound freely, there is a possibility that if the emission of the warning sound is held stopped, the warning sound may not emit when important even in situations in which the warning sound is required.
Furthermore, although a system that automatically emits a warning sound according to various criteria, such as a road state outside the vehicle, a time zone, the presence or absence of pedestrians, has been proposed in recent years, when the user stops the emission of the warning sound, a time lag occurs unavoidably before the warning sound is outputted automatically after the user has stopped the emission of the warning sound.
In addition, when the user controls the system arbitrarily to stop the warning sound under conditions that the safeness is not ensured, there is a possibility that a running time interval during which pedestrians do not notice an approach of the vehicle occurs. This possibility does not satisfy the essential purpose of the warning sound emitting device, and causes a high risk of accidents.
For example, patent reference 1 discloses a vehicle warning device including a restriction prohibiting means for, when a start of the vehicle (self-vehicle) is detected, prohibiting the stop of a warning or reduction of the output level of the warning even if the distance between the vehicle and any other vehicle is equal to or smaller than a reference distance.
However, this device is not based on a case in which the user can control the emission and the stop of the warning, and is limited to operations at the time of starting the vehicle.
Therefore, in a case in which the vehicle exists in an area in which the vehicle needs to emit the warning sound directed outside the vehicle, the device cannot prevent the risk of the user stopping the warning sound.
The present invention is made in order to solve the above-mentioned problem, and it is therefore an object of the present invention to provide a sound-directed-outside-vehicle emitting device that enables a user to control whether to enable or disable the stop of a warning sound according to whether the vehicle is running through a high-risk (or dangerous) zone.